Landspout near Midway Airport: Chicago records first tornado within city limits since 2006

CHICAGO -- Officials with the National Weather Service, and FOX6's sister station WGN in Chicago say the city recorded its first tornado within city limits since September of 2006 this week -- on Tuesday, August 9th.

According to the National Weather Service, a "landspout" formed on a lake breeze boundary on Tuesday afternoon around 4:00 p.m.

The National Weather Service says the landspout was spotted by Melanie Harnacke, an FAA contract observer on duty at Midway Airport.



It was estimated to have begun at 3:48 p.m. and it dissipated by 3:58 p.m.

The National Weather Service reports this was the first tornado within Chicago city limits since a brief F-0 on the campus of Loyola University on September 22nd, 2006.

The National Weather Service describes a landspout as follows:

"A landspout is a tornado with a narrow, rope-like condensation funnel that forms while the thunderstorm cloud is still growing and there is no rotating updraft - the spinning motion originates near the ground. In the case of the Chicago landspout, there was no rain shower or thunderstorm, just cumulus clouds along the lake breeze. Therefore, without a rain shower or thunderstorm, there was no way for the NWS Chicago radar to detect any rotation in the area where the landspout occurred."





Additional landspout definitions

From the National Weather Service Glossary:

"A tornado that does not arise from organized storm-scale rotation and therefore is not associated with a wall cloud (visually) or a mesocyclone (on radar). Landspouts typically are observed beneath Cbs or towering cumulus clouds (often as no more than a dust whirl), and essentially are the land-based equivalents of waterspouts.

Unlike most tornadoes which form beneath a rotating (supercell) thunderstorm, landspout tornadoes form when an area of preexisting rotation near the ground becomes positioned beneath a rapidly developing thunderstorm cloud. The quickly rising air lifting into the cloud stretches the area of rotation near ground level vertically, resulting in an intensification of the spin and the formation of a landspout tornado. Normally landspout tornadoes don't last very long or get very strong, though they can do minor damage before dissipating."